Polydopamine-Modified Nanolime with High Kinetic Stability in Water for the Consolidation of Stone Relics

Abstract

As a promising inorganic nanomaterial for the conservation of arenaceous sandstone-based relics such as wall painting, ancient building, stone heritage etc., nanolime (NL) has drawn increasing attention in recent years. Usually, NL needs to be dispersed into an alcoholic solution when applied. Nevertheless, a back-migration phenomenon of NL to the surface of the stone and delayed carbonation of NL enabled by alcohol do not guarantee good preservation effects. Dispersing NL into water can avoid the above issues. However, NL water suspension shows extremely poor kinetic stability, greatly restricting the penetration of NL into stone relics as well as bringing unfavorable impacts to the treated stone heritage. Here, we develop a facile method to synthesize polydopamine (PDA)-modified NL (PDA@NL). Characterizations demonstrate that PDA is uniformly distributed on the surface of NL particles though hydrogen bonds. In addition, the presence of PDA reduces the size of NL particles and achieves the highest specific surface area of NL reported to date. More importantly, water suspension of PDA@NL is far more stable than that of pure NL. The kinetic stability mechanism of PDA@NL in water is attributed to the lessened spatial interactions between NL particles, which is realized by the coverage of PDA on the surface of NL particles. Furthermore, the coverage of PDA does not inhibit carbonation. Within 105 h, NL in PDA@NL completes carbonation and obtains 93.7% calcite, which is comparable to that of NL suspension. Permeability tests prove that the PDA@NL suspension penetrates far deeper through stone specimens compared with the NL suspension. Additionally, PDA@NL presents good consolidation performances for stone samples. Our work opens a new direction for the modification of NL that will boost the studies of NL-modified materials as well as the conservation of cultural heritage.

[Retracted] The Characteristics and Paths of the Dissemination of Intangible Cultural Heritage in the Form of Animation in the New Media Environment

“…We have to think about new channels and ways of disseminating intangible cultural heritage. In the face of the transition between tradition and modernity, intangible cultural heritage culture needs to be combined with the form of animation, which plays an important role [ 11 ]. Animation in the protection and dissemination of intangible cultural heritage mainly can be carried out through the three latitudes as shown in Figure 4 .…”

Realizing Nanolime Aqueous Dispersion via Ionic Liquid Surface Modification to Consolidate Stone Relics

“…Nowadays, conservators are increasingly aware that cultural heritage conservation heavily relies on the material with well properties. − Nanolime (NL), a well-known nanomaterial in heritage conservation, has been paid close attention due to its remarkable compatibility (after carbonation) with wall paintings, stone relics, etc. − Nevertheless, how to improve the penetration depth of NL in heritage is significant and intractable. The conventional approach is dispersing NL into alcoholic solution.…”

“…The conventional approach is dispersing NL into alcoholic solution. However, this method usually causes a back-migration phenomenon of NL in heritage objects because of the fast evaporation of the alcoholic solution, which cannot ensure a satisfying consolidation efficacy for cultural relics. ,− Dispersion of NL in water can prevent NL from back-migrating. However, NL is unstable in water and thereby its penetration in cultural relics is very limited at this situation.…”

“…22 Our group prepared a polydopamine (PDA)modified NL (PDA@NL) that is able to enhance NL kinetic stability in water in ∼300 min and achieves a deeper penetration depth in stone relics. 5 Yet, similar to polysaccharide molecule-modified NL, PDA@NL is a suspension in water and still easy to aggregate. Therefore, it is urgently needed to realize an NL water dispersion with high kinetic stability.…”

“…The synthesis of polydopamine-modified NL (PDA@NL) follows our previously reported work. 5 First, a CaCl 2 solution containing dopamine hydrochloride was prepared by dissolving CaCl 2 •2H 2 O and dopamine hydrochloride into the mixture of DMF and OPPE following stirring. Second, NaOH aqueous solution was poured into the mixture of the solution of CaCl 2 and dopamine hydrochloride.…”